There are so many of them in china that it's hard to count.
168Gamer and IOPQ are the biggest MMO dev forums in china.
If by "Black District" you mean the Black Market. It exist but very completely hidden away and the requirements are ridiculously extremely.
To apply, according to my research, you need to be
* A Chinese Resident, Forgeiners are never allowed.
* Must have serious developer experience. High C++,SQL,ASM, Web development, is required
* You need to have at least 1 MMO game that you obtained that the general public does not have, and must not be bought (as in, you completely did the action to get the file)
If you meet those requirements, you'll be able to get in.
But where do you go to apply? I don't know. My research for private servers isn't that far ahead. It's hard when you don't know Chinese.